Measure oxygen concentrations in lakes, streams, rivers, estuaries, and coastal waters with the HOBO U26 Dissolved Oxygen Data Logger. This affordable and precise data logger is recommended for aquatic biology and hydrology research projects. The HOBO U26 uses RDO® Basic (Rugged Dissolved Oxygen) optical DO sensor technology and is easy to maintain.
U26-001 data logger
DO sensor cap
Calibration Boot with sponge
Our HOBO U26 Dissolved Oxygen logger has been part of a multi-year evaluation of DO loggers and sensors by the Alliance for Coastal Technologies (ACT), and the results have been published online. This provides an un-biased report of how our U26 performs in lab and field conditions. Note that our response letter with our added recommendations is attached at the end of this report on pages 58 and 59.
Affordable, high performance dissolved oxygen (DO) monitoring with 0.2 mg/L accuracy
Optical DO sensor technology for long-lasting calibration with less maintenance
HOBOware Pro's Dissolved Oxygen Assistant software corrects for measurement drift from fouling; provides salinity-adjusted DO concentrations and percent saturation
Optical USB interface for high-speed, reliable data offload
Easy-to-replace DO sensor cap lasts six months
NOTE: For DO measurements in saltwater, an adjustment for salinity is required. For waters with small changes in salinity (<2 ppt), a salinity meter reading typically provides enough accuracy. For environments with greater salinity changes, we generally recommend the HOBO U24-002-C conductivity logger . If you need DO in Percent Saturation, barometric pressure data is required, which can be logged with a HOBO Water Level Data Logger (U20-001-04).
In what environment does this data logger operate?
This data logger operates in an underwater environment.
What measurements does this data logger support?
The U26-001 data logger supports the following measurements: Dissolved Oxygen and Temperature
0 to 30 mg/L
0 to 20 mg/L; 0 to 35°C (32 to 95°F)
± 0.2 mg/L up to 8 mg/L; ± 0.5 mg/L from 8 to 20 mg/L
To 90% in less than 2 minutes
DO Sensor Cap Life:
6 months, cap expires 7 months after initialization
Temperature Measurement/Operating Range:
-5 to 40°C (23 to 104°F); non-Freezing
To 90% in less than 30 minutes
21,700 sets of DO and temperature measurements (64 KB total memory)
1 minute to 18 hours
±1 minute per month at 0 to 50°C (32 to 122°F)
3.6 V lithium battery; factory replaceable
3 years (at 5 minute logging)
100 m (328 ft)
Black Delrin®, PVC, EPDM o-rings, silicone bronze screws; rated for saltwater use
39.6 mm diameter x 266.7 mm length (1.56 x 10.5 inches)
464 g (16.37 oz)
The CE Marking identifies this product as complying with all relevant directives in the European Union (EU).